Sphingomyelinase compositions and use thereof

ABSTRACT

The use of sphingomyelinase to increase the levels of skin and mucosal ceramides, as well as dermatological and cosmetic compositions containing same which are suitable for topical application are disclosed.

The present invention relates to the use of sphingomyelinase to increasethe levels of skin and mucosal ceramides, and dermatological andcosmetic compositions suitable for topical application containing same.

Ceramide (N-acylsphingosine) is a lipid metabolite which has recentlybeen proposed as an important intracellular messenger released insidethe cell within a few hours of stimulation with various agents or as aresult of serum deprivation, and is related to cell blockade in theG0/G1 phase and apoptosis. Ceramide is currently regarded as a secondmessenger in the context of the sphingomyelin signal transductionpathway. It is released by sphingomyelin as a result of the effect ofsphingomyelinases, which are forms of phospholipase C specific forsphingomyelin. Inside the cells, ceramide can influence growth anddifferentiation, regulate protein secretion, induce DNA fragementationand apoptosis, and increase the synthesis and secretion of cytokines.The molecular mechanisms underlying these various different actions areas yet not entirely known. More is known, on the other hand, aboutextracellular agonists which cause the release of ceramide. Hydrolysisof sphingomyelin occurs rapidly after exposure of the cells to exogenoussphingomyelinases or to agonists which activate endogenoussphingomyelinases. Such agonists include TNF-α, F as ligand, interleukin1-β, IFN-γ, 1α, 25-dihydroxyvitamin D₃ and NGF.

Sphingomyelinase-containing cosmetic compositions are already known.Japanese Patent Publication 63 216813 discloses such a compositionwherein the sphingomyelinase obtained therein aims at counteracting thephysiological decrease of this enzyme in aging skin, thus promoting theconversion of sphingomyelin to ceramide which, in turn, brings about abeneficial moisturising effect on the skin.

The Japanese publication, however, does not disclose or in the leastsuggest that these compositions might be used therapeutically fortreating dermatological disorders. Moreover, sphingomyelinase isobtained via a cumbersome and complex extraction method from tissues ofhigher animals, such as brain and liver.

The importance of ceramide in the skin metabolism shall be clearlyapparent from what follows here below.

The main cellular constituents of the epidermis are keratinocytes,melanocytes, Langerhans cells, fibroblasts, endothelial cells andmacrophages. Mono- and polymorphonuclear leukocytes can infiltrate theskin in the course of inflammation or tumours. The intracellular space,on the other hand, consists mainly of neutral lipids, glyco-proteins,protein degradation products, desmosomes, active enzymes, products ofsebaceous glands and ceramides. As long as this “bricks and mortar”structure is intact, the skin is endowed with both a protective layerand a selectively permeable filter.

During the differentiation process of the epidermis, which starts withcell division in the basal layers and ends with the death ofkeratinocytes and the development of the lipid barrier, the cells modifytheir lipid synthesis capability. The result is that the basal layer ofthe epidermis is characterized by phospholipids and cholesterol, whereasthe outermost layer is characterized by cholesterol, free fatty acids,and, above all, ceramides. The lipids of the horny layer, the maincomponent of which consists of sphingolipids, play a crucial role inmaintaining the permeability barrier of the epidermis to water. Thesphingolipids are extruded from the lamellar bodies of the granularcells of the epidermis. Ceramides (sphingolipids), which make up 43-46%of the horny layer, are the main polar lipids of the horny layer andplay a fundamental role in the barrier function of the skin againstwater leakage in cell adhesion and in the differentiation of theepidermis. Literature data indicate that ceramides are synthesised denovo in the epidermis via phospholipid-like intermediates. They arepresent in fairly high concentrations in the horny layer (up to 40% oftotal lipids).

Like the appearance of the surface of the skin, its functionalproperties also undergo changes with ageing. Ageing skin ischaracterized by a reduced water content in the horny layer associatedwith reduced transdermal leakage of water. It has been shown that theceramide 2: sphingolipid ratio decreases with age. The drop in ceramideassociated with ageing may be responsible for the dehydration of theskin which is observed in the course of ageing.

In addition, abnormal ceramide levels (deficiencies) have been detectedin atopic eczema, dermatosis and dermatitis, in particular atopicdermatitis, and psoriasis. Recently, an inborn deficiency of ceramide 1has been found in autosomal recessive sphingolipidosis. Equally wellknown are generalised forms of sphingolipidosis such as Fabry's disease,Gaucher's disease and Tay-Sachs disease. Sjögren-Larsson syndrome isassociated with a deficiency of ceramide 1 and 6 with attendantdestruction of the normal skin barrier.

In the light of the foregoing, it is obviously useful to maintain highlevels of ceramide in the skin. It will additionally be understood thatthe use of sphingomyelinase proves advantageous also at mucosal level.

There are currently available on the market numerous products containingceramides obtained by extraction methods or synthesis and used indermatology and cosmetics. The topical external application of ceramidesis proposed for remodelling the cutaneous lipid barrier altered byageing, drugs, detergents, physical agents, etc. Such exogenousadministration does not allow for the possibility that there may bequalitative and/or quantitative variations in ceramide due to age andanatomical site, seasonal factors and diseases. Clearly, then, theexogenous administration of ceramide acts only in an additive sense(endogenous+exogenous ceramide) and not in a modulatory sense(variations in ceramide according to season, anatomical site, possibledisease processes in progress, etc.).

Surprisingly, we have now found that high levels of neutral, but notacid, sphigomyelinase are present in the cells and that sphingomyelinaseis capable of inducing the generation of ceramide in the skin andmucosa.

Consequently, one object of the present invention is to provide for theuse of sphingomyelinase to produce dermatological or cosmeticcompositions suitable for topical application in order to increase thelevel of ceramides in the skin and mucosa.

According to the invention, the sphingomyelinase is preferably extractedfrom Gram-positive bacteria, Gram-negative bacteria, lactic bacteria ormixtures thereof. Lactic bacteria should preferably be chosen from amongthe following: Lactobacillus acidophilus, Lactobacilus brevis,Lactobacillus buchneri, Lactobacillus casei, Lactobacillus catenaforme,Lactobacillus cellobiosus, Lactobacillus crispatus, Lactobacilluscurvatus, Lactobacillus delbrueckii, Lactobacillus fermentum,Lactobacillus jensenii, Lactobacillus leichmanii, Lactobacillus minutus,Lactobacillus plantarum, Lactobacillus rogosae, Lactobacillussalivarius, Bifidobacterium adolescentis, Bifidobacterium angulatum,Bifidobacterium bifidum, Bifidobacterium breve, Bifidobacteriumcatenulatum, Bifidobacterium dentium, Bifidobacterium eriksonii,Bifidobacterium infantis, Bifidobacterium longum, Bifidobacteriumplantarum, Bifidobacterium pseudocatenulatum, Bifidobacteriumpseudolongum, Steptococcus lactis, Streptococcus raffinolactis andStreptococcus thermophilus.

According to a preferred embodiment of the invention, the cells are usedin the form of lyophilized or sonicated cells.

According to the present invention, the sphingomyelinase can furthermorebe used as a cutaneous permeation or absorption enhancer, either aloneor in admixture with other enhancers, for preparing pharmaceutical orcosmetic compositions suitable for transdermal administration.

A further object of the present invention is to provide dermatologicalor cosmetic compositions characterized by the fact that they contain anamount of sphingomyelinase effective for producing an increase in thelevel of ceramides in the skin or mucosa.

According to the invention, the sphingomyelinase contained in suchcompositions is preferably extracted from Gram-positive bacteria,Gram-negative bacteria, lactic bacteria or mixtures thereof. Lacticbacteria should preferably be chosen from among the following:Lactobacillus acidophilus, Lactobacillus brevis, Lactobacillus buchneri,Lactobacillus casei, Lactobacillus catenaforme, Lactobacilluscellobiosus, Lactobacillus crispatus, Lactobacillus curvatus,Lactobacillus delbrueckii, Lactobacillus fermentum, Lactobacillusjensenii, Lactobacillus leichmanii, Lactobacillus minutus, Lactobacillusplantarum, Lactobacillus rogosae, Lactobacillus salivarius,Bifidobacterium adolescentis, Bifidobacterium angulatum, Bifidobacteriumbifidum, Bifidobacterium breve, Bifidobacterium catenulatum,Bifidobacterium dentium, Bifidobacterium eriksonii, Bifidobacteriuminfantis, Bifidobacterium longum, Bifidobacterium plantarum,Bifidobacterium pseudocatenulatum, Bifidobacterium pseudolongum,Steptococcus lactis, Streptococcus raffinolactis and Streptococcusthermophilus.

According to a preferred embodiment of the invention the cells containedin the compositions are in the form of lyophilized or sonicated cells.

The dermatological or cosmetic compositions of the invention shallpreferably comprise from 1×10² to 1×10¹⁵ CFU of lactic bacteria per gramof composition.

The dermatological or cosmetic composition of the invention may alsocontain exogenous ceramide or products containing exogenous ceramide,sphingomyelines, fatty acids, cholesterol, ceramidase inhibitors,protease inhibitors, immunomodulators, vitamins, growth factors,surfactants, emulsfiers, stabilizers, lipids, rheological additives,humidifiers, antioxidants, preservatives, colouring agents, lakes,pigments, auxiliary substances (e.g. adds, bases, propellants) andfunctional substances (astringents, antiseborrhoeic agents,anti-dandruff agents, deodorants, skin purifiers, keratogenous agents,moisturizers, anti-xerosis agents, smoothing agents, screens,sunscreens, pigmenting agents, antidepigmenting agents, emollients,restorers, eutrophic agents, anti-wrinkle agents, antiradicals,stiffeners, anti-stretch-mark agents, vasoprotectors, anti-skin-rashagents, soothing agents, anti-cellulitis agents, tonifying agents,stimulants, hypereluting agents, epilators, nail protectors).

Lastly, the dermatological or cosmetic compositions of the invention canbe formulated in the form of liquid, semiliquid, semisolid, solid orpowder products, e.g. in the form of creams, ointments, lotions,capsules, pearls, ovules, mascara, eyewashes, toothpaste, mouthwashes,lipsticks, liposomes, soap, shaving soap, tonics, douches, enteroclysissolutions, shampoos, anti-dandruff preparations, impregnated and/ormedicated bandage or gauze, patches, medicated emulsions, transdermalgels or patches.

To confirm the ability of these bacteria to induce the generation ofceramide in the skin, the following experiment was conducted, based onthe detection of neutral sphingomyelinase, the enzyme responsible forgenerating ceramide in human skin.

METHODS Assay of Neutral and Acid Sphingomyelinase in Lactic Bacteria

10 mg of lyophilized Streptococcus thermophilus were resuspended in 500μl of buffer containing HEPES 20 mM, pH 7.4, MgCl₂ 10 mM, EDTA 2 mM, DTT5 mM, NA₃VO₄ 0.1 mM, Na₂MoO₄ 0.1 mM, p-nitrophenylphosphate 30 mM,β-glycerophosphate 10 mM, ATP 750 mM, PMSF 1 μM. leupeptin 10 μM,pepstatin 10 μM (Sigma Chemical Co.) and 0.2% Triton X-100 (for theassay of neutral SMase activity) or 500 μl of 0.2% Triton X-100 (for theassay of acid SMase activity). The samples thus prepared were thensubmitted to lysis by sonication (for 1 min and 50 sec, alternating 10sec of sonication with 10 sec of rest) using Vibracell sonicator (Sonicand Materials Inc. Danbury, Conn.). The sonicated samples were thencentrifuged for 30 min at 14,000 rpm, at 4° C., the supernatant wasremoved and the protein concentration determined using the Bio-RadLaboratories kit (Richmond, Calif.).

100 μg of sample were incubated for 2 hours at 37° C. in a buffer (50 μlfinal volume) containing HEPES 20 mM, MgCl₂ 1 mM, pH 7.4, and 2.25 μl of[N-methyl-14C]sphingomyelin (SM) (0.2 μCi/ml, a.s. 56.6 mCi/mmol,Amersham).

To measure the activity of acid sphingomyelinase, 100 μg of bacteriallysate were incubated for 2 hours at. 37° C. in a buffer (50 pd finalvolume) containing sodium acetate 250 mM, EDTA 1 mM, pH 5.0, and 2.25 μlof [N-methyl-¹⁴C]SM. The reaction was blocked by the addition of 250 μlof chloroform:methanol:acetic acid (4:2:1). The phospholipids wereextracted, analysed on plates by TLC and hydrolysis of SM quantified bymeans of autoradiography and liquid scintillation. The SMase present inthe sonicated bacteria was indicated as Units/mg protein. One unit ofneutral SMase hydrolyses 1 μmole of sphingomyelin per min at pH 7.4 at37° C. One unit of acid SMase hydrolyzes 1 nmole of SM toN-acetylsphingosine and choline phosphate per hour at pH 5.0 at 37° C.

Preparation of a Cream and Treatment (Duration and Modality)

A cream was prepared (using a dehydrating base cream) containingsonicated lactic bacteria [2 20-g tubes of base cream plus 1 vial ofsonicated lactic bacteria (1×10¹² CFU) in 20 ml of water] and the effectof daily applications of the cream on the ceramide levels of the hornylayer of the epidermis of the forearm was assayed in 8 volunteers asindicated in Table 1 here below. TABLE 1 No. Sex Age 1 male 45 2 female39 3 female 29 4 female 27 5 female 33 6 female 32 7 male 38 8 female 25

The subjects were instructed to self-administer the control cream andthe experimental cream containing the lactic bacteria twice per day(approximately 1 ml, morning and evening). The control cream was applieddaily on the right forearm, while the experimental cream was applied onthe left forearm. Both creams were rubbed in until they were fullyabsorbed. Lipids of the horny layer of the epidermis were collected fromthe forearm by washing with 250 ml of 99.5% ethanol prior to the startof application of the cream (T0) and one week (T1) after the start oftreatment. The ethanol extracts were concentrated with a rotaryevaporator and then evaporated dry. The dried samples were dissolved in2 ml of chloroform, dried with nitrogen and subjected to DAG kinaseassay for ceramide quantification (Amersham, Buckinghamshire, GreatBritain). After three extraction runs, the lipids were dried again withnitrogen, dissolved in 100 μl of chloroform and subjected to thin layerchromatography (TLC), using chloroform:methanol:acetic acid (65:15:5,v/v/v) as the run solvent. Phosphorylated ceramide was detected byautoradiography. The patches corresponding to ceramide-1-phosphate werecut and subjected to a count of the radioactivity present usingscintillation liquid in a P-counter. The amount of ceramide present wasdetermined on the basis of a standard curve obtained with authenticceramide (type III; of bovine brain; Sigma Chemical Co., St. Louis,Mo.).

RESULTS Sphingomyelinase Activity in Lactic Bacteria

The levels of neutral sphingomyelinase activity in the sonicated lacticbacteria samples were approximately 2×10⁻⁷ units/mg of bacteria. No acidsphingomyelinase activity was detected.

Effects of Sonicated Lactobacillus on Ceramide Levels in the Skin

The ceramide levels in the ethanol extracts obtained as described in the“Methods” section are given in Table 2 here below and the respectiveautoradiographs are shown in FIG. 1. It can be noted, regardless of thesubstantial subjective basal variability, that the use of both creamsgave rise to an increase in ceramide levels in the forearm skin of allthe subjects analyzed. However, the increase was much more marked andsignificant after application of the cream containing lactic bacteria.What is more, the effect of the experimental cream on ceramide levelscould be detected earlier compared to that induced by the base cream,thus indicating faster action of the former. TABLE 2 Right forearm Leftforearm No. T0 T1 T0 T1 1 0 0 0 1,941 2 223 567 147 298 3 8 500 24.2 7004 8 347 2 300 5 300 500 435 1,390 6 400 480 236 340 7 30 28 180 270 8 10280 12 278

1-11. (canceled)
 12. A method of enhancing the cutaneous permeation orabsorption or a transdermally administered pharmaceutically activesubstance in a pharmaceutical composition, said method comprisingincluding in said pharmaceutical composition a sphingomyelinase obtainedfrom lactic bacteria in the form of sonicated cells.
 13. The method ofclaim 12 wherein the lactic bacteria is selected from the groupconsisting of Lactobacillus acidophilus, Lactobacillus brevis,Lactobacillus buchneri, Lactobacillus casei, Lactobacillus catenaforme,Lactobacillus cellobiosus, Lactobacillus crispatus, Lactobacilluscurvatus, Lactobacillus delbrueckii, Lactobacillusfermentum,Lactobacillus jensenii, Lactobacillus leichmanii, Lactobacillus minutus,Lactobacillus plantarum, Lactobacillus rogosae, Lactobacillussalivarius, Bifidobacterium adolescents, Bifidobacterium angulatum,Bifidobacteriumbifidum, Bifidobacterium breve, Bifidobacteriumcatenulatum, Bifidobacterium dentium, Bifidobacterium eriksonii,Bifidobacterium infantis, Bifidobacterium longum, Bifidobacteriumplantarum, Bifidobacterium pseudocatenulatum, Bifidobacteriumpseudolongum, Streptococcus lactis, Streptococcus raffinolactis andStreptococcus thermophilus.
 14. The method of claim 12 wherein thecomposition contains 1×10² to 1×10¹⁵ lactic bacteria per gram ofcomposition.